CARACAS, Venezuela  Venezuelan President Hugo Chavez is facing a “complex” recuperation period after six hours of surgery for cancer Tuesday, his vice president said, as he warned Venezuelans to prepare for “difficult” days ahead.

Nicolas Maduro, flanked by National Assembly President Diosdado Cabello and Oil Minister Rafael Ramirez as he addressed Venezuelans in a nationwide broadcast, didn’t provide updated information on Chavez’s health after saying Tuesday night that the operation had been successful.

“It’s very clear that our people need to accompany him in his treatment process but also that our people are serenely prepared to face these hard, complex and difficult days we are living,” Maduro said in comments broadcast on state television.

The 58-year-old Chavez named longtime ally Maduro, who has close ties to Cuba, as his heir apparent before traveling to the communist island for a fourth operation in 18 months. Chavez, a self-declared socialist, has urged Venezuelans to vote for Maduro in the event he’s unable to remain in office.

Maduro said Chavez is being attended by Cuban and Venezuelan doctors and experts from other countries he didn’t name, he said.

The vice president led a late-night vigil attended by hundreds in downtown Caracas on Tuesday night, asking Venezuelans to light candles for Chavez to give him strength.